In the surgical treatment of fractures in the maxillofacial area, as well as fractures of the foot and hand, a trend toward preferring ever-smaller implants can clearly be noted. The reason for this is the generally increased understanding of the biomechanical bases of osteosynthesis. In the field of treating maxillofacial fractures, more attention can be paid to the cosmetic results of osteosynthesis, thanks to the miniaturization of implants.
In the field of hand surgery, restrictions on movement in the area of the fingers can be avoided. Osteosynthetic implants in the fingers can be placed under the tendons. In the case of an implant with a large cross-section, the tendons need no longer be extended to their full length.
The dimensions of the so-called mini-implants (screws and plates) are in the area of 0.8 mm-2.0 mm. Problems in the area of packaging, storage and manipulation during surgery arise due to this miniaturization. Handling in the operating room, particularly in the maxillofacial area, has proved difficult. Depending on the degree of severity of the fracture or correction, up to 40 bone screws may be required. These screws must be taken individually by the operating room nurse from a so-called screw rack, checked for length, placed on a screwdriver and given to the surgeon. The surgeon must, in turn, insert them through the osteosynthesis plate into pre-drilled screw holes. During the transfer of the screw and the attempted insertion of the screw, it often falls off the screwdriver, into the wound or onto the OR floor. The attempt to find a lost screw is often excessively time-consuming, given their dimensions (0.8 mm diameter.times.4.0 mm) and extends the time spent in surgery. The frequent loss of screws in the OR, and during packing and sterilization, causes unnecessary costs for the hospital.
An additional problem in dealing with mini-screws arises during their implantation. After the surgeon has selected the osteosynthesis plate proper for the fracture in question, he positions the plate over the fracture. He then drills the hole for the screw (0.5-1.5 mm diameter) through one of the plate holes. After drilling, he takes the screw needed from the OR nurse and screws it into the bone through the plate. The problem here often is finding the core drill hole in the bone, since the bone surface is covered with blood or soft tissue and the plate can slip on the smooth bone surface.